Arlington Heights reviews December CNG garbage-truck explosion; fire chief urges safer battery disposal and new response rules

Arlington Heights — At a Feb. 18 Arlington Heights Village Board meeting, Fire Chief Lance Harris delivered an internal review of a Dec. 6 incident in which a contracted Groot garbage truck caught fire and exploded, injuring members of the responding public-safety crews but not causing any life-threatening injuries to residents.

Harris told the board the department is treating the presentation as an internal review while Groot’s own investigation remains open, and said the department is sharing lessons learned with the contractor and neighboring departments.

The presentation focused on how CNG (compressed natural gas) systems behave in fire, how pressure-relief devices (PRDs) are intended to operate, the timeline of the December event and immediate operational changes the Village and Groot have agreed to. Harris said the explosion is not ‘‘normal behavior of a CNG storage system during a fire’’ and explained how PRDs are designed to vent upward to prevent catastrophic failure.

The review described CNG as primarily methane, lighter than air and flammable, and noted that odorant (mercaptan) is added to aid leak detection. Harris said Groot has operated CNG vehicles in the community since 2010 and that its Elk Grove fleet includes about 165 vehicles, of which about 15 run on CNG and about 50 run on diesel. He described CNG cylinders as composite-wrapped tanks with pressure-relief devices located in openings along each side of the truck. On the truck involved in December, Harris said, there were five PRD openings per side — ten PRDs total — and that only one PRD needs to operate to vent the entire daisy‑chained system.

Harris reviewed the December timeline and response: the truck had completed a morning route, emptied at the transfer station around noon, returned to…